This project examines the function of various oral tissues in individuals with alterations of normal oral function due to disease or therapeutic procedures. Major efforts have been directed at the evaluation of patients complaining of xerostomia (oral dryness) utilizing the impatient and outpatient services of the Dry Mouth Evaluation Clinic. Specific diagnostic approaches have been developed to aid in establishing the causes of salivary gland dysfunction and defining criteria necessary for management decisions. Normal parameters have been established for salivary scintigraphy with technetium pertechnetate in a healthy control population and a simple rating scale for scintiscans constructed. A treatment protocol for patients with secretory hypofunction related to active or past radiation therapy continues, employing a regimen of oral administration of the parasympathomimetic drug, pilocarpine. Clinical and laboratory studies focusing on the causes and character of the salivary gland component of Sjogren's syndrome, an autoimmune exocrinopathy, have advanced. Treatment protocols for primary Sjogren's syndrome are continuing. In addition, detailed studies of salivary-associated oral complaints (eg. taste and oro-pharyngeal swallowing disorders) have progressed. The cells infiltrating the labial minor salivary glands in patients with Sjogren's syndrome have been studied. These are predominantly T-lymphocytes of the memory (helper/inducer) subtype, although only a small percentage were found to express the gamma-delta form of the T cell receptor. There was also increased expression of specific proto-oncogenes in these cells.